I can’t imagine this would be an issue, especially if you get a USB drive that all the systems can use. Alternatively, you could connect it to your “server” and then share it out so everyone other system can backup to it over the network. Most importantly, make sure you encrypt the drive, or at least your backups, using some type of strong encryption like what’s offered by PGP or Acronis’ products.
Definitely check out www.drobo.com , I have heard good things about that drive.
In any networking area or setup, even every client and server has the best and powerful hardware capabilities if they don’t meet with each other or not compatible, they could never communicate and exchange information. The best thing you have to consider is the compatibility of every computer unit and their configurations in any network environment.